Onyxia ui doesn't start if param userNamespace is set to false

Hi !

We have an onyxia instance in a cluster where user namespace are not allowed and only groups namespace are allowed. If we set the param userNamespace to false onyxia web doesn't start. Onyxia ui show a popup with this error message:

```
Error: Wrong assertion encountered: "There should be only one project without group (user project)"
```